SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b78ee5ae40f9d1f281691440b0bfe547fb91bcb7cb872f361e89793bf8e8bc22' 
  AND token = 'wOWNOxNjCAm8fdnDLu1BcrxqffZOXfoaHTPmPJpwQj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}